Local area network (LAN) is a collection of hardware and software that connects individual PCs and workstations together for resourcing, sharing, messaging services and work group computing. A type of basic LAN interfaced design is the Ethernet. The Ethernet typically uses a base band or a broad band transmission. The base band transmission carries a single digital signal at data rates as high as 100 megabytes per second. Data is placed directly on the media without modulation and only one signal is allowed on the cable at a time. Broad band transmission carries multiple data channels. It requires a large band width or operating frequency range in order to allow many carrier frequencies on one cable.
One type of Ethernet is the Thicknet Ethernet or 10BASE5. This version is a coaxial cable which carries baseband signaling. The cable is grounded only once every 500 meters to prevent ground loops. A tap is connected to the Ethernet thick coaxial cable to provide electrical connection to a transceiver which in turn provides signal to a network device. A typical tap connector provides both signal and signal ground connections to the transceiver, however, the signal ground is not grounded to earth ground.
Because there is such a large distance between grounding points, electrostatic discharge (ESD) and common electromagnetic interference (EMI) are two potential problems which can exist between the grounding points. It is necessary to protect taps which are remote from the grounding point from the ESD and common mode EMI.
U.S. Pat. No. 5,221,216 shows a typical connector for a coaxial connector which is capacitively coupled to ground. The signal ground of the coaxial connector is connected to a shell on the conductor. A around contact having resilient arms is secured to the ground on the circuit board. The resilient arms are used to secure a chip capacitor between the ground shell and the ground contact thereby forming a shunt pathway for EMI and ESD which is on the signal ground of the coaxial connector. without actually forming an electrical connection between the signal ground and the earth ground.
It would be desirable to provide a tap connector in which the signal ground is capacitively coupled to earth ground.